1. Field of the Invention
The present invention relates to systems for controlling the closing of a camera shutter.
2. Description of the Prior Art
Systems for controlling the closing of a photographic camera shutter in response to the initiation of shutter closure are well known such as the automatic exposure control systems utilized in the Kodak Instamatic model 30 and 40 cameras. Such systems, however, are powered by a conventional battery which is constantly drained as the system is utilized and must be replaced several times during the normal life of the camera. In addition, in such prior art systems, electrical energy is utilized to hold the shutter open for the required exposure time, a solenoid being energized to accomplish this. This requirement is a further drain on the battery power supply of such cameras resulting in the eventual replacement thereof.
Magnetic generators, such as the types described in U.S. Pat. Nos. 3,132,268; 3,693,033; 3,718,828; 2,764,020; 3,398,302 and 3,130,332 are well known, although such generators have normally been of low efficiency and thus have not gained wide acceptance or utilization. Because of such low efficiency, such generators have not proved to be an acceptable alternative to conventional battery power supplies. Such inefficiencies become particularly critical where the amount of power utilized is large compared to the practical and efficient size of the generator desired.
As mentioned above, solenoids having movable armatures are well known; however, the basic principle of operation of such prior art solenoids depends on energization of the coil to latch the armature, thereby requiring a power drain to accomplish this latching function. In utilizations such as for control of the closure of a camera shutter, such power drain to latch the shutter open is undesirable and may become critical.
These disadvantages of the prior art are overcome by the present invention.